The invention concerns a holder for use in a machine for decorating articles, for holding such an article.
In this specification the term decorating is used broadly and thus embraces, for example, applying matter such as a pattern or graphics to an article or applying printing to an article.
One form of holder for holding an article in a machine for decorating articles includes a base member with a format plate arranged releasably over the base member and having an opening therein for receiving the article. Disposed on the base member is a thin layer of a soft material on which the article is disposed during a decoration procedure. The thin layer of soft material, which is generally a plastic film, is glued directly on to the base member. The plastic film thus forms a soft support which is intended to ensure that the surface of the article, being the surface by which the article rests on the holder, is not damaged, for example by scratching, in particular due to relatively coarse particles of dust or other smaller particles which may be deposited on the holder. Particles of that nature will occur in any space or room which does not satisfy special cleanliness conditions. The provision of the film thus ensures that, if a pressure which acts in a direction towards the holder is applied to the respective article in the holder, for example by virtue of the doctor of a screen printing mechanism or by an impression cylinder, any particles which are between the article and the holder and which are therefore on the film will be pressed into the soft film, so that this article and also subsequent articles to be held in the holder will not be scratched or otherwise damaged by such particles.
The films must be renewed frequently depending on the demands made in terms of the surface quality of the articles and the cleanliness of the air in the area around the printing mechanisms used for applying decoration to the respective articles. Renewal of the film may also be required, for example, when the format plate has to be changed when modifying the holder from dealing with articles of one format to articles of a different format. If the articles have sharp edges which occur, for example, in the form of burrs or other sharp projections arising in manufacture of the articles, for example, in an injection molding process, then the film will suffer from incisions of greater or lesser severity and possibly also other damage, in particular along the configuration for receiving the respective article, which is defined by the opening in the format plate. Such incisions and other damage mean that the same film cannot be used for articles of a larger format. It is to be assumed in this respect that, to simplify handling and inventory, irrespective of the size of the respective articles to be treated and thus the size of the receiving configuration for the individual article, as is defined by the opening in the format plate, films of the same size will be at least predominantly used.
In addition, the pressure loading applied to the article by a doctor or impression cylinder, which is transmitted through the article onto the film material which is supporting the article, means that this film material also experiences in the course of time, in spite of a degree of elasticity which is possibly inherent therein, a certain degree of permanent compression which normally excludes the use of the same film for an article of a larger format, as in that case, due to compression of the film, the film would be of differing thicknesses in the region in which an article of a smaller format has been accommodated.
One of the consequences involved in frequent changes in the films, as are required due to the above-described circumstances and possibly also other factors, is that the stoppage times of a machine used for decorating articles tend to be considerably increased and thus the productivity of such a machine is reduced. In the case of the above-discussed holder, the operation of changing the film involves first removing the format plate, whereupon the film is withdrawn from the base member which is generally also of a plate configuration. After that, the adhesive which has possibly remained on the base member has to be removed before a fresh film can then be fitted in properly oriented relationship to the base member. It will be appreciated that those steps require a considerable amount of time. In this case consideration is also to be given to the fact that, for example, modern screen printing or offset printing machines, by virtue of the level of productivity required, have a large number of holders, for example thirty two or thirty four, which means that a correspondingly large number of films has to be renewed. Examples of machines of that nature are disclosed in U.S. Pat. Nos. 5,899,143 and 6,082,256, to which reference is accordingly made for incorporation of the disclosure thereof into the content of this specification.
An object of the present invention is to provide a holder for use in a machine for decorating articles, for holding such an article, which at least noticeably reduces disadvantages of the previous structures without a significant increase in expenditure to achieve that aim.
Another object of the present invention is to provide a holder for holding an article in a machine for decorating such articles, such as a printing machine, which is so designed that the machine stoppage times required to replace an article-supporting part of the holder can be substantially reduced.
A further object of the present invention is to provide a holder for holding an article in a machine for decorating such articles, which is of a simple structure to permit ready disassembly thereof for replacement of parts requiring renewal.
Still a further object of the invention is to provide a method of renewing in a holder for an article a part of the holder which is effective to support the article during a decoration or printing process.
Yet a further object of the invention is to provide an apparatus for decorating or printing on articles, including a holder for holding the article during decoration or printing in a secure manner without involving damage to the article.
In accordance with the principles of the present invention the foregoing and other objects are attained by a holder for holding an article in a machine for decorating articles, the holder comprising a base member with a format plate arranged releasably over the base member and having an opening therein for receiving an article to appropriately position it for the decoration procedure. An intermediate plate is arranged releasably between the base member and the format plate, and has a surface which is remote from the base member. A thin layer of soft material is carried on that remote surface of the intermediate plate, for suitably supporting the article thereon.
In accordance with a preferred feature of the holder of the invention the layer of soft material can be in the form of a self-adhesive film of plastic material, for example polyurethane. Depending on the configuration of the holder and in particular the opening formed therein for receiving the article, the film can also be of a multi-part nature, for example in such a way that a substantial part of the film covers over the actual receiving means for accommodating the article and serves as a support for the article, while at least a further portion of the film is disposed between the intermediate plate and the format plate thereabove.
So that the intermediate plate and the format plate can be rapidly fitted to the base member and also to allow them to be rapidly released therefrom, a preferred feature of the invention provides that the intermediate plate and the format plate can be fixed to the base member by a magnet arrangement. In that respect, different magnets mounted in the base member can be provided for the intermediate plate and the format plate, in such a way that the magnets holding the intermediate plate in position are substantially aligned with the upper boundary surface of the base member, whereas the magnets which serve to mount the format plate in position project with respect to the surface of the base member by an amount which approximately corresponds to the total of the thicknesses of the intermediate plate and optionally the film, the intermediate plate being provided with holes into which the magnets for holding the format plate extend, the upper boundary surface of the magnets, which is remote from the base member, being approximately aligned with the upper boundary surface formed by the surface of the film which is remote from the intermediate plate.
In accordance with another preferred feature of the invention, the holder may include means for moving the intermediate plate with the layer of soft material and the format plate positively into the correct position relative to the base member and fixing those components in that appropriate position.
Further objects, features and advantages of the invention will be apparent from the detailed description of the invention and of a preferred embodiment below.